The present application relates to a secondary battery including a cathode, an anode, and an electrolytic solution, an electronic device using the same, an electric power tool using the same, an electrical vehicle using the same, and an electric power storage system using the same.
In recent years, various electronic devices such as a mobile phone and a personal digital assistant (PDA) have been widely used, and it has been strongly demanded to further reduce their size and weight and to achieve their long life. Accordingly, as a power source for the electronic devices, a battery, in particular, a small and light-weight secondary battery capable of providing a high energy density has been developed. In these days, it has been considered to apply such a secondary battery not only to the foregoing electronic devices but also to various applications represented by an electric power tool such as an electrical drill, an electrical vehicle such as an electrical automobile, and an electric power storage system such as a home electrical power server.
As the secondary battery, secondary batteries using various charge and discharge principles have been widely proposed. Specially, a secondary battery using insertion and extraction of ions such as lithium ions is considered promising, since such a secondary battery provides a higher energy density than lead batteries, nickel cadmium batteries, and the like.
The secondary battery includes a cathode, an anode, and an electrolytic solution. The cathode and the anode respectively contain a cathode active material and an anode active material that insert and extract ions such as lithium ions. In the secondary battery, in order to obtain a high battery capacity, as a solvent of the electrolytic solution, a mixed solvent of a cyclic ester carbonate and a chain ester carbonate and the like are used.
Electrolytic solution compositions largely affect performance of the secondary battery. Therefore, various studies have been made on the electrolytic solution compositions. Specifically, to improve cycle characteristics and the like, it is proposed to make the electrolytic solution contain an unsaturated carbon bond cyclic ester carbonate or a halogenated cyclic ester carbonate (for example, see Japanese Unexamined Patent Application Publication Nos. 2002-289256, 2003-297419, and 2006-086058 and Japanese Patent No. 4365013). In this case, a coat is formed on the surface of an anode, and therefore a decomposition reaction of the electrolytic solution resulting from a reaction with an anode active material is suppressed. As the unsaturated carbon bond cyclic ester carbonate, vinylene carbonate or the like is used. As the halogenated cyclic ester carbonate, 4-fluoro-1,3-dioxolane-2-one or the like is used.